Bellanca 7KCAB N36339 accident near Renton, Washington

Probable cause

Maintenance personnel’s inadequate post-maintenance inspections that resulted in the total loss of engine power due to a blockage in the air intake.

NTSB analysis

The airplane had recently undergone an annual inspection, and the accident flight was the first flight since being out of maintenance. After making a normal departure and touch-and-go landing, the pilot receiving instruction applied full power. As the airplane reached an altitude of about 400 feet above ground level (agl), the engine abruptly stopped producing (total) power. The airplane could not maintain level altitude and during the subsequent off-airport landing, the airplane was substantially damaged when it collided with a tree.

Postaccident examination revealed that the air induction box contained a piece of bunched up paper that likely restricted the inlet cavity. As part of the annual inspection, a repair person completed a small fiberglass patch and painting on the lower cowling. He could not recall the specific repair on the airplane but said he often placed paper in the induction to prevent debris from entering the engine. After the maintenance, the airplane sat for a day with the lower cowling not fastened but maintenance personnel did not recognize the blockage. They also did not find the paper during the post-maintenance inspections and returned the airplane into service with an unsafe condition.

Text from the NTSB. Open the NTSB docket for WPR20LA180 for the full record.